VSE/ESA Performance when running under VM/ESA
Last Updated 07 January 2005
From 20 October 1997:
The following is a summary of VSE guest performance for the two workloads
we measure. In additional are a list of comments from which to help
qualify the "it depends" statement that should always be included with
this material. The majority of this information was taken from the
VM/ESA Release 2.2 Performance Report GC24-5673-01 or the
VM/ESA 2.1.0
performance report GC24-5801-00.
- ITR
- Internal Throughput Rate = measure of work per CPU second
- ETR
- External Throughput Rate = measure of work per Wallclock second
- %VM
- percentage of total processor time used by VM/ESA Control Program
DYNAPACE Workload
Results from Dynapace Workload measurements on 9121-320. VM/ESA
2.1.0 and VSE/ESA 2.1.0.
Environment |
ITR |
ETR |
%VM | Pct Nat
ITR | Pct Nat
ETR |
Runid |
|---|
| Native |
18.66 |
7.63 |
0% |
100% |
100% |
L1NATxxx |
| V=R Dedicate |
16.48 |
7.57 |
8% |
88% |
99% |
L1R88PF0 |
| V=V MDCache |
13.22 |
12.51 |
26% |
71% |
164% |
L1V88PF0 |
Results from Dynapace Workload measurements on 9121-480. VM/ESA
2.1.0 and VSE/ESA 2.1.0.VSE run with turbo dispatcher as 2-way.
Environment |
ITR |
ETR |
%VM | Pct Nat
ITR | Pct Nat
ETR |
Runid |
|---|
| Native |
31.18 |
7.88 |
0% |
100% |
100% |
L2NATxxx |
| V=R Dedicate |
28.89 |
7.49 |
10% |
93% |
95% |
L2R88PF1 |
| V=V MDCache |
20.25 |
12.33 |
28% |
65% |
156% |
L2V88PF3 |
PACEX Workload
Results from PACEX Workload measurements VM/ESA
1.2.2 and VSE/ESA 1.3.2.
Environment |
ITR |
ETR |
%VM | Pct Nat
ITR | Pct Nat
ETR |
Runid |
|---|
| Native |
35.46 |
6.16 |
0% |
100% |
100% |
LBNAT132 |
| V=R Dedicate | 25.38 | 5.94 | 16% | 72% | 96% | LB78REX1 |
| V=R | 19.14 | 5.98 | 34% | 54% | 97% | LB78REX6 |
| V=R MDCache | 18.93 | 9.31 | 36% | 53% | 151% | LB78REX2 |
| V=V | 18.24 | 6.13 | 37% | 51% | 100% | LB78VEXK |
| V=V MDCache | 19.21 | 10.70 | 36% | 54% | 174% | LB78VEXN |
| V=V MDC+VDisk | 19.83 | 16.15 | 35% | 56% | 262% | LB78VEY1 |
VSECICS Workload
Results from VSE/CICS workload measurements. VM/ESA
2.1.0 and VSE/ESA 2.1.0. 9121-320.
Environment |
ITR |
ETR |
%VM | Resp
Time |
Pct Nat
ITR | Pct Nat
ETR |
Runid |
|---|
| Native | 77.91 | | 0% | 0.196 | 100% | | NAT3208A |
| V=R Dedicate | 72.93 | 65.76 | 3% | 0.226 | 94% | | L1R88C90 |
| V=V MDCache | 65.32 | 60.21 | 12% | 0.237 | 84% | | L1V88C90 |
Results from VSE/CICS workload measurements. VM/ESA
1.2.2 and VSE/ESA 1.3.2.
Environment |
ITR |
ETR |
%VM | Resp
Time |
Pct Nat
ITR | Pct Nat
ETR |
Runid |
|---|
| Native | 87.95 | 60.81 | 0% | 0.210 | 100% | 100% | NAT3207B |
| V=R Dedicate | 80.93 | 57.64 | 5% | 0.241 | 92% | 95% | VR13207C |
| V=V | 69.56 | 49.51 | 14% | 0.202 | 79% | 81% | VV13207K |
| V=V MDCache | 69.64 | 48.24 | 15% | 0.190 | 79% | 79% | VV13207F |
Things it depends on
-
What do you mean by performance? ITR? ETR? Response Time?
-
Obviously, the workload as seen above is a factor. ETR focus for
batch workloads and Response time focus for CICS workload.
-
MDC results beneficial if enough storage and CPU capacity exist.
-
Preferred guests require I/O Assist for high ITR values, sharing
DASD can minimize this.
-
Extra hypervisor layers can impact results. For example, with VM/ESA
running in a logical partition, only 1 V=R machine is possible and
I/O Assist is not possible.
-
For environments that do not benefit from I/O Assist, the larger the
percentage of I/Os that are DASD, the better ITR picture. This is
due to fast CCW translation which is only valid for DASD I/O.
-
The slower the real DASD I/O hardware, the better the ETR and response
time numbers are since minidisk cache and virtual disk in storage
minimize I/O elapsed time. Even with control unit cache, MDC is
faster.
-
I/O patterns. High lock file I/O activity will benefit more from
virtual disk in storage. Higher data re-references will show benefits
from minidisk cache. Read-once data patterns will not see benefit.
-
Overall system utilization. VM/ESA has background work such as
monitor, MDC arbiter, accounting, etc. that occurs that is not
proportional to activity on the system. This 'overhead' is relatively
constant so when spread across more transactions, the base overhead
becomes smaller. Several of the benchmark measurements above were
made with low system utilization (less 70% CPU).
Update, January 7, 2005
z/VM 5.1.0 drops support for preferred guests and for I/O Assist.
This has implications for VSE workloads, especially in
processor-constrained environments. For more information,
visit this tip.
Back to the Performance Tips Page
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